Remove Skipped Tests in Viz telemetry testing

It appears that all failures of telemetry_perf_unittests and telemetry_unittests
when running VizDisplayCompositor have either been fixed, or since disabled as
the tests where more general failures.

This updates the isolated script for running these with Viz to no longer have
any skipped tests.

This only affect the Linux Viz FYI bot

TEST=telemetry_unittests_viz, telemetry_perf_unittests_viz

Bug: 799594
Change-Id: I7fafbe3c5ccb7b41fefb08f630c531c26dbba47c
Reviewed-on: https://chromium-review.googlesource.com/1151720Reviewed-by: Dirk Pranke <dpranke@chromium.org>
Cr-Commit-Position: refs/heads/master@{#578413}

testing/buildbot/chromium.fyi.json

@@ -1065,10 +1065,7 @@
       {
         "args": [
           "--xvfb",
-          "--extra-browser-args=--enable-features=VizDisplayCompositor",
-          "--skip=contrib.cluster_telemetry.screenshot_unittest.ScreenshotUnitTest.testScreenshot",
-          "--skip=core.perf_benchmark_unittest.PerfBenchmarkTest.testVariationArgs",
-          "--skip=core.perf_benchmark_unittest.PerfBenchmarkTest.testVariationArgsReference"
+          "--extra-browser-args=--enable-features=VizDisplayCompositor"
         ],
         "isolate_name": "telemetry_perf_unittests",
         "name": "telemetry_perf_unittests_viz",
@@ -1090,9 +1087,7 @@
       },
       {
         "args": [
-          "--extra-browser-args=--enable-features=VizDisplayCompositor",
-          "--skip=telemetry.internal.backends.chrome_inspector.inspector_page_unittest.InspectorPageTest.testCaptureScreenshot",
-          "--skip=telemetry.internal.browser.tab_unittest.GpuTabTest.testScreenshot"
+          "--extra-browser-args=--enable-features=VizDisplayCompositor"
         ],
         "isolate_name": "telemetry_unittests",
         "name": "telemetry_unittests_viz",

testing/buildbot/test_suites.pyl

@@ -1602,9 +1602,6 @@
       'args': [
         '--xvfb',
         '--extra-browser-args=--enable-features=VizDisplayCompositor',
-	'--skip=contrib.cluster_telemetry.screenshot_unittest.ScreenshotUnitTest.testScreenshot',
-	'--skip=core.perf_benchmark_unittest.PerfBenchmarkTest.testVariationArgs',
-	'--skip=core.perf_benchmark_unittest.PerfBenchmarkTest.testVariationArgsReference',
       ],
       'swarming': {
         'hard_timeout': 960,
@@ -1615,8 +1612,6 @@
       'isolate_name': 'telemetry_unittests',
       'args': [
         '--extra-browser-args=--enable-features=VizDisplayCompositor',
-	'--skip=telemetry.internal.backends.chrome_inspector.inspector_page_unittest.InspectorPageTest.testCaptureScreenshot',
-	'--skip=telemetry.internal.browser.tab_unittest.GpuTabTest.testScreenshot',
       ],
       'swarming': {
         'shards': 4,